Presently, commercial synthetic organic polymer powders are made by grinding of extruded polymer pellets often under cryogenic temperature conditions. Grinding is undesireable as a result of being highly energy-intensive and sensitive to contamination from the grinding equipment used and from environmental pollution. Due to the erratic nature of the grinding process, it is practically impossible to controlling quality, particle size, and distribution of polymer powders. Ball milling of extruded polymer pellets also suffers from similar problems.
Some polymer materials, such as ultra-low molecular weight polyethylene, cannot even be ground or ball milled to form particulates as a result of their waxy nature.
An object of the present invention is to provide a method for making polymer particulates from polymer materials in a manner that overcomes the aforementioned problems heretofore associated with grinding or ball milling to produce commercial polymer powders.
Another object of the present invention is to provide a method for making polymer particulates from polymer materials that heretofore could not be ground or ball milled to particulate form.
Still another object of the present invention is to provide a method for making polymer particulates by gas atomizing molten polymeric material in a manner to provide controlled particle shape, particle size and particle size distribution.
Still a further object of the present invention is to provide a method for gas atomizing molten polymeric material to form polymer particulates without the need for the addition of flow modifiers, such as oils and greases or molybdenum disulfide, to the polymer material to lower viscosity.
Still an additional object of the present invention is to provide atomized polymer particulates with particle shape, particle size and particle size distribution controlled as desired.
Another object of the present invention is to provide atomized polymer particulates which heretofore could not be produced on a mass-production basis by grinding or ball milling of extruded material.
Still a further object of the present invention is to provide atomized polymer particulates of improved quality with reduced contamination from flow modifiers and other additives heretofore used.
A further object of the invention is to provide improved atomizing apparatus for gas atomizing fluid polymer materials, inorganic materials, metallic materials and others.